Having a baby can be one of the most terrifying experiences a woman ever endures—she is, after all, literally pushing another human out of her body. And Serena Williams’ recent account of her own horrific ordeal last year, which came out in an interview with Vogue on Wednesday, highlights how scary and, sometimes, life-threatening becoming a mother can be. Not only did the tennis superstar develop blood clots in her lungs the day after she had her daughter—when she self-diagnosed her condition, a nurse thought she was “confused”—Williams also popped open her C-section stitches from intense coughing and developed a hematoma in her abdomen. When she finally left the hospital, she spent the first six weeks of her daughter’s life unable to get out of bed.

Immediately after the Vogue profile came out, women on social media pointed out just how common Williams’ frightening experience is. One woman tweeted: “If Serena Williams with all her money, power, access & reach had her voice IGNORED - what do you think happens to poor, immigrant Black women?” The National Advocates for Pregnant Women also chimed in: “Serena Williams wasn't taken seriously after she gave birth & knew she had a pulmonary embolism. This speaks volumes about how little our society values and supports pregnant women & how significantly racism & sexism influence our health care system.”

Williams’ story isn’t the first this month to draw attention to the plight of black mothers and their health. Less than two weeks ago, Erica Garner, the 27-year-old who became an activist against police brutality after her father Eric Garner was choked to death by an NYPD officer, died after developing a rare postpartum condition characterized by a weakening of the heart due to factors such as stress. She’d given birth in August to a boy she named after her father.

The risk of pregnancy-related deaths is three to four times higher for black women than it is for white women, according to the CDC. (It’s why the US is the worst developed country for maternal mortality rates, and that number is rising.) A recent ProPublica investigation found that the inequities that plague black women’s health care are not simply a matter of poverty and access: In fact, a 2016 report found that black college-educated mothers who gave birth in New York City hospitals were more likely to suffer severe complications than white women who never graduated from high school.

Experts say what’s driving the disproportionate toll on black mothers is, simply put, institutionalized racism. Linda Goler Blount, the president and CEO of The Black Women's Health Imperative, told Broadly in 2016: "Researchers and physicians don't understand what kind of toll being a black woman in this society takes on our health emotionally and physically.”

According to a 2016 study from the University of Virginia, racial bias plays a role in how medical providers assess black patients’ complaints of pain. Other examples of institutionalized racism, says Black Mamas Matter Alliance steering committee chair Elizabeth Dawes Gay, include doctors not listening to, spending less time with, and providing a lower quality of care to their black patients.

“There is research showing that racism and racial discrimination play a particular role in influencing health outcomes—not just in maternal health but in health more broadly,” Gay says. “But we also see that in maternal health through these stress mechanisms that actually wear on the body.”

To describe that very process, Arline Geronimus, a professor at the University of Michigan School of Public Health, coined the term “weathering.” She told ProPublica that weathering “causes a lot of different health vulnerabilities and increases susceptibility to infection, but also early onset of chronic diseases, in particular, hypertension and diabetes”—all of which disproportionately affect black people at much younger ages than white people.

To many people, the fact that someone as famous and respected as Serena Williams could still face this kind of dangerous skepticism is astounding. But her story resonated because it's so sadly commonplace: “Having this story out there,” Gay says, “means that now people who haven’t thought about black maternal health a day in their life are seeing it and can now consider it as something that happens to black women even as popular and celebrated as Serena Williams.”

“Providers need to do a better job of listening to women,” she continues. “They need to trust women. Serena obviously knew her body—she knew what was going on with her. They should have respected that and respected her opinion when she first brought it up.”

Williams’ experience also drives home the importance of women not being afraid to advocate for themselves, Gay says. “For women to trust themselves and to be bold in speaking up, and to not let the historical power dynamics between patient and provider disrupt their health.”